Objects accelerate when hitting surface

Hey i once saw a tutorial where a 2d component was described which you could attach to the ground and every Rigidbody touching the ground was accelerated in a given direction with a given force.

I just cant find the video or the name of the component again and i woud be really thankfull if you knew what im talking about.

Thanks for your time and help. ^^

i can only think of Surface Effector or physic materials, i imagine that the first one.